Abstract

A celestial reference frame at X/Ka-band (8.4/32GHz) has been constructed using fifty-one 24-h sessions with the Deep Space Network. We report on observations which have detected 436 sources covering the full 24 h of right ascension and declinations down to −45°. Comparison of this X/Ka-band frame to the S/X-band (2.3/8.4 GHz) ICRF2 shows wRMS agreement of 200 micro-arcsec (μas) in \( \alpha cos\delta \) and 290 μas in δ. There is evidence for zonal errors at the 100 μas level. Known errors include limited SNR, lack of phase calibration, troposphere mismodelling, and limited southern geometry. The motivations for extending the ICRF to frequencies above 8 GHz are to access more compact source morphology for improved frame stability, to provide calibrators for phase referencing, and to support spacecraft navigation at Ka-band.